Gallery: Graphics chipset shootout

The integrated graphics market is probably one of the least glamorous but most important since most PCs rely on these chipsets. There is much contention over which CPU is more energy efficient, which chipset does better at gaming, and which chipset is better at playing back video. (See George Ou's full shootout, AMD 690G versus Intel G965.) First up: power consumption.

The power consumption results as you can see are mixed and it has good news and bad news for both AMD and Intel. The good news for AMD is that they’re able cut their clock speeds and voltages more drastically resulting in a silent PC that dropped down to a measly 54 watts of power consumption in idle which is 12 watts lower than the Intel system’s idle state. This low power state can mostly be maintained while the user is typing up documents and playing back MP3s or other digital audio streams. Slightly more stressful tasks will take the AMD 690G-based PC up to a 70 to 80 watt state. The bad news for AMD is that its peak power consumption is substantially higher than Intel’s chips and anyone who’s constantly playing games on their AMD based PC or anyone who leaves Folding at Home running 24×7 is going to end up with a much bigger electric bill.
The good news for Intel is that their system is able to maintain very reasonable power consumption levels even under peak loads. The Intel G965 system with an E6600 CPU is able to get by with 93 watts even under a full load. The bad news for Intel is that their idle state - while respectable - isn’t as low as it could be had Intel been a little more aggressive in cutting clock speeds. The Intel G965 system ran at 66 watts idle but these results might be slightly unfair to Intel since the motherboard used in the Intel system is a full ATX motherboard with twice the number of memory DIMM slots, twice the number of PCI-E connectors, and 50% more SATA connectors. The AMD system is using a stripped down MicroATX motherboard so we might be comparing the mileage of a four seat vehicle to a two seat vehicle.

Published: July 24, 2007 -- 06:22 GMT (23:22 PDT)

Caption by: George Ou

If we look at some power consumption results from Scott Wasson’s article at TechReport.com, we can see that Wasson gets the opposite results for idle power consumption where the Intel E6600 system uses 121 watts whereas the AMD X2 5600+ system uses 126 watts in idle. Now Scott Wasson is actually using the exact same video card for both systems so the only difference is in the motherboard and CPU. Take a look at the chart I compiled from Wasson’s report. The difference here is explained purely in the difference in motherboards. The Asus M2N32-SLI motherboard is a more fully loaded motherboard than the Intel D975XBX2 board.

There will also be significant improvements in Intel’s new 3-series chipset in energy efficiency. The P35 chipset for example is able to shave off 8 watts in idle mode compared to similarly equipped 965 motherboards in idle mode. Furthermore, I have reliable sources that are telling me about Intel’s latest “Stepping G” revision of the Core 2 processor line that promises to slash power consumption by a significant amount and it will be due this quarter. The new Stepping G manufacturing process is able to shift Intel’s entire line of processors down one notch on the TDP (Thermal Design Power) scale. This will for example allow Intel to take their 3.0 GHz “Clovertown” quad-core processor (used in Apple Workstation computers as of April 2007) from 150 watts max TDP to 120 watts so that it can be used in 8-core Server configurations. The existing 65 watt TDP CPUs will most likely use even less power. When I get my hands on a G35 motherboard and/or Stepping G CPU, I’ll do a follow up to this article.

So the lesson here is that the power consumption is heavily dependent on the Motherboard used and the feature set of that motherboard. Larger motherboards with more sockets and connectors will naturally have more power consumption and smaller MicroATX boards like the MSI K9AGM2-FIH will take less power. If we factor out the motherboards, Intel and AMD processors have roughly the same idle power consumption but AMD processors consume far more power under peak loads.

To figure out why AMD is able to cut their power consumption so drastically, let’s look at what’s happening to the voltage and CPU clock speed. Here we have screen shots of the CPU-Z utility showing the difference between AMD’s Cool’n'Quiet technology versus Intel’s SpeedStep technology.

AMD is willing to slash their clock speed from 2.8 GHz with an FSB multiplier of 14 all the way down to a 5x multiplier which results in a 1 GHz processor. This is all done in real time depending on the workload and as soon as the computer needs more performance, the FSB multiplier is jacked back up to 14. This allows AMD to cut most of the power consumption in its CPUs.

Intel does something similar with SpeedStep by cutting their FSB multiplier from 9x to 6x which takes the clock speed from 2.4 GHz to 1.6 GHz and this results in a more modest power saving in Intel processors. While that may be good enough to almost match AMD on idle power consumption, why not make it even better? If the computer is going to sit there doing nothing most of the time, Intel should try and cut the idle power consumption of a PC using their mainstream CPUs down to 40 watts or below. It isn’t good enough to just have an efficient sleep state since users don’t want their computers to fall asleep because they want to be able to access the files and desktop remotely at any time. We can also forget about asking end-users to configure wake-on-LAN because even a former professional network engineer like me has a hard time over coming some of the difficulties.

Video playback quality has also been one of the more contentious issues. To test DVD video playback quality, I used the HQV benchmark from Silicon Optics and took screenshots of what I saw. First we’ll start with the diagonal filter test which shows how well it handles the “Jaggies”. As you can see, AMD’s ATI X1250 integrated video card failed badly and all three moving bars were distorted with severe “Jaggies”.

Since a lot of DVDs were converted from 24 fps film, the 3-2 pull-down film conversion test can reveal ugly patterns and the rendering of detail. With the AMD 690G, the race car and fence are all blurry and you can see an unnatural pattern in the stands.

Published: July 24, 2007 -- 06:22 GMT (23:22 PDT)

Caption by: George Ou

As you can see, the Intel G965 passed film conversion test with flying colors.

Published: July 24, 2007 -- 06:22 GMT (23:22 PDT)

Caption by: George Ou

The next test is a color bar and resolution test, which checks to see if the DVD player can play back very fine details and whether or not the color is rendered faithfully. Once again, Intel passes...

Published: July 24, 2007 -- 06:22 GMT (23:22 PDT)

Caption by: George Ou

...while AMD fails. The AMD 690G failed to produce a stable image. The entire screen flickered badly on this test and the details in the green square I enclosed were not visible at all which means the resolution is very poor. Even the words “Belle Nuit” are blurry and the numbers in the grey bars in the lower left hand corner are barely legible whereas the Intel G965 renders it faithfully.

Published: July 24, 2007 -- 06:22 GMT (23:22 PDT)

Caption by: George Ou

Doing a gaming benchmark on integrated graphics solutions is kind of like comparing dumb and dumber. But since we’re in the mood to compare, I have to give the users some idea of what kind of gaming experience they can expect. To test one of the more popular games, I dragged over a copy of my Valve folder which contains all of my Steam games which includes Half-life 2 and Counter Strike Source.

Note that G965 version 1.56 Beta drivers for Vista were used for just these gaming tests. Intel has lagged horribly behind on providing full 3D acceleration and it’s been more than a year since the G965 launched yet we won’t see production 3D optimized drivers until September 2007. As you can see, these are pretty pathetic results though AMD’s newer 690G is the winner.

To figure out why AMD is able to cut their power consumption so drastically, let’s look at what’s happening to the voltage and CPU clock speed. Here we have screen shots of the CPU-Z utility showing the difference between AMD’s Cool’n'Quiet technology versus Intel’s SpeedStep technology.